Semiconductivity in oxides
The discussion draws on the extensive studies by Philips’ researchers [7] and [8] and by D.M. Smyth and co-workers [4]. Several cases of oxide systems in which the conductivity is controlled by the substitution of aliovalent cations are given in Chapter 4. For instance, Sb5þ can replace Sn4þ in SnO2 and be compensated by an electron in the conduction band conferring n-type conductivity (see Section 4.1.4). However, models for oxide systems are generally more complex than for